Background: Employment is a central component of economic independence and is widely viewed as an essential element of social control. Whether frequent drug use reduces the likelihood of employment or obstructs hours worked, wages, and job commitment is therefore an important question about which there remains uncertainty. Methods: We improve on shortcomings of prior research through a monthly within-person analysis of a population at high-risk of both drug use and poor employment outcomes. We present multilevel models of the 18 months spent on the street preceding the arrest that led to incarceration in minimum/medium security facilities in Ohio from a random sample of 250 adult male inmates interviewed during the outset of a prison spell. Results: The analysis reveals consistently strong, negative effects of frequent drug use on employment, hours worked, and wages in the month following frequent drug use, including marijuana, cocaine, heroin, and prescription opioids. As well, frequent drug use (with the exception of marijuana) undermines job commitment during the months that participants are employed. Conclusions: The consequences of frequent drug use for future employment are consistently negative within this criminal justice sample. Results suggest that lower levels of drug use may improve the success of post-release employment programs. In a context of increasing concern over rising opioid and heroin, but also cocaine and marijuana abuse, the findings suggest a renewed focus on and perhaps expansion of evidence-based drug treatment among populations embedded within the criminal justice system, particularly if employment constrains criminal behavior.